*{
  margin:0;
  padding:0;
}

#main{
  margin:50px auto;
  width:370px;
  font-size:1.1em;
}

#calc{
  margin-left:50px;
  width:70px;
}
input,label,span{
  margin:5px 0;
  font-size:1em;
  padding-left:5px;
}
#width-val,#height-val{
  color:red;
  margin-left:52px;
}
span {
  color:red;
}
